It is known for example from my U.S. Pat. No. 4,759,058 to provide a standard desktop-telephone handset with a shoulder rest basically comprising a contoured shoulder cradle adapted to sit on the user's shoulder and a clamp arrangement that engages the back of the handset. Thus the telephone is supported on the user's shoulder against his or her ear, and the user's hands are left free for other tasks. In such a system (see also U.S. Pat. Nos. 2,348,138, 2,476,221, 2,493,954, 2,816,963 and 3,567,871 as well as British patent No. 726,879 and German patent document 2,004,701) the clamp or clip always engages the back part of the stem extending between the mouthpiece and earpiece of the handset.
Such arrangements are not, however, usable on a standard cellular-telephone handset because invariably such a handset carries substantially all of the dialing and operating buttons and incorporates substantial circuitry. Thus such a handset typically is of substantially the same width from its upper earpiece end to its lower mouthpiece end from which the cord extends, that is it is as wide at the stem as at both ends. For comfort such a handset is not straight, either being curved or formed of two parts extending at a wide obtuse angle to each other. The buttons are provided on the back of the handset so that they can be operated with one hand, normally when the device is cradled, and so that they do not get in the way of the user's chin when the handset is being talked into.
Unfortunately such a construction militates against the use of a shoulder rest because only very few shoulder-rest units can actually be clamped to such handsets and none of the known models can be fitted to the handsets without rendering them useless. This is particularly troublesome as such telephones are usually provided in automobiles and are used by persons who are simultaneously driving their vehicles. The phone therefore takes one hand away from the task of driving, creating a potential safety problem.
A partial solution to this problem has been the provision of so-called hands-free telephones which are nothing other than speaker-phone adapters. These devices add, however, to the normally already marginal sound quality of cellular telephones, so that they represent at best a poor answer to the problem of how to use a cellular telephone safely while driving.